Text of my ‘When Worlds Collide’ column published in Ceylon Today newspaper on 4 July 2014

How a tsunami warning system works. AFP FILE PHOTO

Timely warnings about on-coming disasters can literally save lives – provided the word reaches those at risk. And they know what to do, and react quickly.

These elements form part of disaster risk reduction, or DRR, now receiving greater attention as the frequency and intensity of disasters keep increasing.

In December 2004, the Indian Ocean tsunami caught Sri Lanka by surprise and some 40,000 lives were lost. Most of those could have been saved if only a simple warning – for coastal evacuation – reached them. There was a tight but useful window of around 90 minutes until the killer waves arrived on our East coast (and a bit longer while they went around the island and hit other coastal areas).

Sri Lanka was not alone. At the time, much of the Indian Ocean was a massive ‘blind spot’ where tsunamis were concerned. There was no tsunami warning system. There was a rudimentary ocean-based seismic detector network, but it was not possible to monitor or analyze sea level changes in real time.

On the delivery front, too, there was no agreed arrangement to cover the crucial ‘last mile’ to reach communities at risk. In contrast, the Pacific Ocean region has had a functional system for over 60 years.

Whatever the hazard, early warnings would work well when adequate technological capability combines with proper decision-making and dissemination systems, and prepared communities.

In the case of tsunamis, an effective warning and mitigation system means people living in vulnerable coastal areas know how to respond when a potentially destructive tsunami may be approaching.

Tsunami warning systems are made up of three components.

First, an international or regional arrangement (like PTWC) that detects earthquakes in real time, evaluates their tsunami-creating potential, looks for sea level changes and issues specific messages.

Second, country disaster management organisations that receive such warning messages and make national or local level decisions (alert? stand-by? evacuate?). They activate communication systems and response plans already agreed upon.

Third, residents in areas at risk are educated and trained.

Since 2004, several regional tsunami warning systems have been set up, covering most coastlines worldwide. The Indian Ocean Tsunami Warning and Mitigation System (ICG/IOTWS) was set up in 2005 and is governed by UNESCO’s Intergovernmental Oceanographic Commission (IOC-UNESCO).

The global seismic network to monitor earthquakes in real time has also expanded considerably. PTWC now receives data from over 600 stations. There is also a core sea level monitoring network in place: some 500 stations feed PTWC with real-time data.

Automated sentinels – called Deep-ocean, Real-time Tsunami Reporting Systems (DARTs) — watch the world’s oceans day and night. These can detect tsunami signals immediately via pressure sensors on the ocean floor. Those signals travel acoustically to surface buoys, from where they are beamed to satellites that relay them to the nearest tsunami warning centres.

Effective tsunami warnings require very rapid evaluation of earthquakes and resulting sea level changes, followed by equally rapid dissemination of the assessment just made. Not every earthquake undersea generates a tsunami.

Good communications is the life blood of this entire ‘relay’. It depends critically on swift communications and on global data networks with real time transmission capabilities. Disaster early warnings are global public goods: open data sharing among national agencies and cross-border collaboration between researchers is routine practice.

Back in 2004, the average time for PTWC to process data rapidly and issue a warning was 18 minutes. By 2014, according to Dr Weinstein, this has been reduced to 7 mins – a tangible improvement when every second counts.

Of course, even the most accurate warning is only as good as its quick and targeted dissemination. There too, progress has been made.

The number and reliability of pathways to send out a warning have increased. Since 2004, the number of mobile phones in use has risen exponentially (expected to pass 7 billion active subscriptions before 2014 ends), and there is much greater signal coverage. Meanwhile, the phenomenal growth of web-based platforms and social media has opened up new opportunities for emergency communications.

Using communications systems like SMS alerting, cell broadcasting, Twitter, Facebook or Google Public Alerts, tsunami warnings can be sent to a mass or niche audience.

Streamlining this process is the Common Alerting Protocol (CAP), a recent global standard that allows emergency alerts and public warnings to be disseminated simultaneously over different systems and applications.

By standardizing the collecting and relaying of all-hazard warnings and reports locally, nationally and regionally, CAP reduces chances for distortion and confusion. It helps to send out consistent messages on mobile phones, radio and television broadcasts, and other networks.

In late 2007, the International Telecommunication Union (ITU), which sets standards for telecom and broadcasting industries, adopted CAP.

False Alarms

CAP emerged just in time – when rapid expansion was taking place in TV, radio, mobile phones and Internet sectors.

“The likelihood of error and distortions getting into warning messages as they pass through multiple links is that much higher now. The complexity of the first-responder system is also that much higher,” notes Prof Rohan Samarajiva, Chair of LIRNEasia.

CAP can also increase the speed of communicating warnings. Says Prof Samarajiva: “In an ideal scenario, the authorized entity will press one button and the conversion of the formatted message to different forms for multiple media and transmission will be done automatically and instantaneously.”

Even when the best monitoring and assessment systems are coupled with the finest dissemination methods, errors of judgement could still happen.

On average, three out of every four tsunami related coastal evacuations in Hawaii later prove unnecessary. That, Dr Weinstein feels, is the “price to pay for the ones that prove correct”.

“Rapid judgement is needed in such situations — and we scientists can’t always get it right! We need to take that chance for the greater good,” he said. “We tell Hawaiians that unnecessary evacuations are inevitable if you want to avoid major tragedies.”

Prof Samarajiva is cautiously optimistic. He says: “We can take some satisfaction that Sri Lanka has contributed to the knowledge needed to reduce death and devastation. But knowledge has to be applied…incorporated into everyday practice, not only by government and private sector officials but also by all citizens.”

His hope: the 10th anniversary of Sri Lanka’s greatest disaster will energize the efforts to build more resilient societies in the Asia Pacific.

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About Nalaka Gunawardene

A science writer by training, I've worked as a journalist and communication specialist across Asia for 25+ years. During this time, I have variously been a news reporter, feature writer, radio presenter, TV quizmaster, documentary film producer, foreign correspondent and journalist trainer. I continue to juggle some of these roles, while also blogging and tweeting and column writing.
There's NOTHING OFFICIAL about this blog. In fact, there's NOTHING OFFICIAL about me! I've always stayed well clear of ALL centres of power and authority.